Heavy metal ions, such as Cd, Hg, Pb, and As, tend to persist in soil without natural degradation and can be absorbed by crops, leading to the accumulation of agricultural products that pose a significant threat to human health. However, the development of a rapid and efficient technique for identifying heavy metals in agricultural products is essential to ensure health and safety. With the knowledge of the extent of damage caused by heavy metals, it becomes imperative to detect the presence of cadmium in the soil, water, and the environment. This study introduces a novel plate approach for quick and precise colorimetric detection of cadmium ions using the Cd(II)-Chrome Azurol S CAS-2,2 '-dipyridyl dipy-Cetylpyridinium Bromide CPB quaternary complex. Our innovative method has shown that at a reaction solution pH of 11, the optimal concentration ratio is CAS (5 x 10-3 M): dipy (0.1 M): CPB (1.0 x 10-3 M) = 4 mL: 1 mL: 1 mL. The most significant fading alert was observed when the ethylenediaminetetraacetic acid (EDTA) chelator was added dropwise to the CAS detection plate, indicating strong chelation of Cd by EDTA. This laboratory-based study established a foundation for future applications in real environmental sample analysis.

Lead (Pb), a prevalent heavy metal contaminant in aquatic environments, has complex effects on the gut microbiome function of aquatic animals. In this study, metagenomic analysis of Bufo gargarizans tadpoles was carried out following Pb exposure. Moreover, histological analysis was performed on the intestines. The results showed that Pb exposure induced histological damage to the intestinal epithelium. Significant differences in microbial abundance and function were detected in the 200 mu g/L Pb group compared to the control group. Specifically, an increase in Bosea and Klebsiella was noted at 200 mu g/L Pb, which potentially could induce inflammation in tadpoles. Notably, the decrease in the abundance of glycoside hydrolases subsequent to exposure to 200 mu g/L Pb is likely to attenuate carbohydrate metabolism. Furthermore, increased fluoroquinolone-related antibiotic resistance genes (ARGs), phenolic-related ARGs, and iron uptake systems following 200 mu g/L Pb exposure might heighten the disease risk for tadpoles. These discoveries augment our comprehension of the influences of Pb on the intestinal well-being of amphibians and offer valuable insights for further assessment of the ecological risks that Pb poses to amphibians.

Soil chemical washing has the disadvantages of long reaction time, slow reaction rate and unstable effect. Thus, there is an urgent need to find a cost-effective and widely applicable alternative power to facilitate the migration of washing solutions in the soil, so as to achieve efficient removal of heavy metals, reduce the risk of soil compaction, and mitigate the damage of soil structure. Therefore, the study used a combination of freeze-thaw cycle (FTC) and chemical washing to obtain three-dimensional images of soil pore structure using micro-X-ray microtomography, and applied image analysis techniques to study the effects of freeze-thaw washing on the characteristics of different pore structures of the soil, and then revealed the effects of pore structure on the removal of heavy metals. The results showed that the soil pore structure of the freeze-thaw washing treatment (FT) became more porous and complex, which increased the soil imaged porosity (TIP), pore number (TNP), porosity of macropores and irregular pores, permeability, and heavy metal removal rate. Macroporosity, fractal dimension, and TNP were the main factors contributing to the increase in TIP between treatments. The porous structure resulted in larger effective pore diameters, which contain a greater number of branching pathways and pore networks, allowing the chemical washing solutions to fully contact the soil, increasing the roughness of the soil particle surface, mitigating the risk of soil compaction, and decreasing the contamination of heavy metals. The results of this study contribute to provide new insights into the management of heavy metal pollution in agricultural soils.

The toxicity is produced for living organisms when the nanomaterials are developed in the natural ecosystem either naturally or if introduced by humans. Nevertheless, there is a huge gap in the research of this area, and investigations are being conducted to determine the potential detrimental impacts of the nanomaterials and the means of eliminating the potential toxicities. In our research, we investigated the potential of zinc oxide nanoparticle (ZnONPs) tolerant Trichoderma pseudoharzianum T113 strains in reducing the toxicity of ZnO NPs in tomato crops. Our research findings of a very thoroughly investigated experiment on mechanism of action revealed that application of T113 in NPs amended soil triggered an appreciable change in the microbial diversity of the soil and improved the population density and diversity of the growth-promoting soil microbes and fungi that produced glomalin, a protein responsible for metal chelating. The amount of glomalin in the soil was significantly improved in soil by T113 strain inoculation. The diversity and abundance of the microbes, having beneficial impacts on plants and the glomalin in soil, drastically reduced the NPs induced toxicity under the application of the T113 strain of T. pseudoharzianum. Plants inoculated with the T113 strain, when grown in NPNP-contaminated soil, exhibited increased growth, enhanced antioxidant activities, improved photosynthesis, and a decline in damage induced by oxidative stress and the accumulation and translocation of Zn. Moreover, applying the T113 strain also reduced the Zn bioavailability in soil contaminated with NPs. These research findings are an eco-friendly and sustainable solution to the ZnO NP toxicity in the host plants.

This study developed a novel geopolymer (RM-SGP) using industrial solid wastes red mud and slag activated by sodium silicate, aiming to remediate composite heavy metal contaminated soil. The effects of aluminosilicate component dosage, alkali equivalent, and heavy metal concentration on the unconfined compressive strength (UCS), toxicity leaching characteristics, resistivity, pH, and electrical conductivity (EC) of RM-SGP solidified composite heavy metal contaminated soil were systematically investigated. Additionally, the chemical composition and microstructural characteristics of solidified soil were analyzed using XRD, FTIR, SEM, and NMR tests to elucidate the solidification mechanisms. The results demonstrated that RM-SGP exhibited excellent solidification efficacy for composite heavy metal contaminated soil. Optimal performance occurred at 15 % aluminosilicate component dosage and 16 % alkali equivalent, achieving UCS >350 kPa and compliant heavy metal leaching (excluding Cd in high-concentration groups). Acid/alkaline leaching tests revealed distinct metal behaviors: Cu/Cd decreased progressively, while Pb initially declined then rebounded. Microstructural analysis indicated that RM-SGP generated abundant hydration products (e.g., C-A-S-H, N-A-S-H gels), which acted as cementitious substances wrapping soil particles and filling and connecting pores, thereby increasing the soil's compactness and improving the solidification effect. Furthermore, heavy metal ions were solidified through adsorption, encapsulation, precipitation, ion exchange, and covalent bond et al., transforming their active states into less bioavailable forms, proving novel insights into the remediation of composite heavy metal contaminated soils and the resource utilization of industrial solid wastes.

Cadmium (Cd) accumulation in Solanum nigrum L. is known to occur mainly in cell walls and vesicles. However, limited research has been conducted on the toxic effects of Cd specifically targeting mitochondria in S. nigrum leaves. This study aims to delineate the impact of Cd accumulation on mitochondrial structure and function in S. nigrum leaves, thereby providing a theoretical foundation for enhancing its application in phytoremediation of Cd-polluted soils. The results showed that the Cd content in mitochondria would gradually reach saturation with the increase of Cd treatment concentration. However, the accumulation of Cd led to osmotic pressure imbalance and morphological changes within mitochondria, which in turn caused a series of impairments in mitochondrial function. Cd severely damaged the energy metabolism function of mitochondria, especially under 200 mu M CdCl2 stress, the mitochondrial ATP content decreased by 90.65 % and the activity of H+-ATPase decreased by 80.65 %. Furthermore, reactive oxygen species (ROS) in mitochondria accumulated mainly in the form of H2O2. Compared with the non-Cd control group, the H2O2 content in the Cd-treated groups (50, 100, and 200 mu M CdCl2) increased by 61.62 %, 186.69 %, and 405.81 %, respectively. The inhibition of cellular respiration by Cd and the sharp increase in ROS exacerbated the oxidative damage in mitochondria. Interestingly, the activities of mitochondrial peroxidase (POD) and dehydroascorbate reductase (DHAR) exhibit remarkable tolerance under Cd stress. Based on these results, we believe that Cd can cause dysfunction and oxidative damage to the mitochondria of S. nigrum leaves.

The environmental threat, pollution and damage posed by heavy metals to air, water, and soil emphasize the critical need for effective remediation strategies. This review mainly focuses on microbial electrochemical technologies (MET) for treating heavy metal pollutants, specifically includes Chromium (Cr), Copper (Cu), Zinc (Zn), Cadmium (Cd), Lead (Pb), Nickel (Ni), and Cobalt (Co). First, it explores the mechanisms and current applications of MET in heavy metal treatments in detail. Second, it systematically summarizes the key microbial communities involved, analyzing their extracellular electron transfer (EET) processes and summarizing strategies to enhance the EET efficiencies. Next, the review also highlights the synergistic microbial interactions in bioelectrochemical systems (BES) during the recovery and removal (remediation) processes of heavy metals, underscoring the crucial role of microorganisms in the transfer of the electrons. Then, this paper discussed how factors including pH values, applied voltages, types and concentrations of electron donors, electrode materials, biofilm thickness and other factors affect the treatment efficiencies of some specific metals in BES. BES has shown its great superiority in treating heavy metals. For example, for the treatments of Cr6+, under low pH conditions, the recovery and removal rate of Cr-6(+) by double chambers microbial fuel cell (DCMFC) can generally reach 98-99%, with some cases even achieving 100% (Gangadharan & Nambi, 2015). For the treatments of heavy metal ions such as Cu2+, Zn2+ and Cd2+, BES can also achieve the rates of treatments of more than 90% under the corresponding conditions of appropriate pH values and applied voltages(Choi, Hu, & Lim, 2014; W. Teng, G. Liu, H. Luo, R. Zhang, & Y. Xiang, 2016; Y. N. Wu et al., 2019; Y. N. Wu et al., 2018). After that, the review outlines the future challenges and the research opportunities for understanding the mechanisms of BES and microbial EET in heavy metal treatments. Finally, the prospect of future BES researches are pointed out, including the combinations with existing wastewater treatment systems, the integrations with the wind energy and the solar energy, and the application of machine learning (ML) in future BES. This article has certain significance and value for readers to better understand the working principles of BES and better operate and control BES to deal with heavy metal pollutants.

The pollution of metal ions triggers great risks of damaging biodiversity and biodiversity-driven ecosystem multifunctioning, whether microbial functional gene can mirror ecosystem multifunctionality in nonferrous metal mining areas remains largely unknown. Macrogenome sequencing and statistical tools are used to decipher linkage between functional genes and ecosystem multifunctioning. Soil samples were collected from subdams in a copper tailings area at various stages of restoration. The results indicated that the diversity and composition of soil bacterial communities were more sensitive than those of the fungal and archaeal communities during the restoration process. The mean method revealed that nutrient, heavy metal, and soil carbon, nitrogen, and phosphorus multifunctionality decreased with increasing bacterial community richness, whereas highly significant positive correlations were detected between the species richness of the bacterial, fungal, and archaeal communities and the multifunctionality of the carbon, nitrogen, and phosphorus functional genes and of functional genes for metal resistance in the microbial communities. SEM revealed that soil SWC and pH were ecological factors that directly influenced abiotic factor-related EMF; microbial diversity was a major biotic factor influencing the functional gene multifunctionality of the microbiota; and different abiotic and biotic factors associated with EMF had differential effects on whole ecosystem multifunctionality. These findings will

The discharge of heavy metals (HMS) from industrial production has severely damaged the natural environment and human health. To address the challenges posed by heavy metals, a novel almond shell biochar (FeSCTS@nBC) modified with FeS and chitosan (CTS) was prepared. Scanning electron microscopy and X-ray photoelectron spectroscopy observations revealed a uniform distribution of FeS particles on the biochar. Adsorption thermodynamics experiments showed that the maximum adsorbed amounts of cadmium (Cd), lead (Pb), and chromium (Cr (VI) and Cr (III)) in FeS-CTS@nBC were 85.6, 89.63, 94.2, and 75.62 mg/g, respectively. Results of soil incubation experiments indicated that FeS-CTS@nBC had a desirable immobilization effect on heavy metals, decreasing the bioavailability of Cd, Pb, Cr (VI), and Cr (III) by 29.43%, 23.93%, 5.75% and 5.23 %, respectively. Density functional theory (DFT) calculations, revealed that the oxygen-containing functional groups on the biochar exhibited stronger adsorption capacities for heavy metals. Plant potting experiments indicated that the paddy grew well in the soil remediated with FeS-CTS@nBC. The Cd content in the roots and leaves of the paddy after nBCS2 repair was reduced by 28.01 % and 55.73 %, respectively. Overall, this work provides a promising low-cost method with a simple production process for mitigation of heavy metals from water and soil.

Rapid urbanization and industrial growth in China have increased brownfield site reclamation, the sustainable remediation for urban transformation and enhancing ecosystem services. However, traditional brownfield safety assessment strategies impose unnecessary costs since excessive remediation. Herein, a comprehensive system integrated by soil self-purification, potential ecological risks and human health risks is developed to investigate the safety of brownfield sites. Indices, including soil environmental loading capacity (SELC), and Nemerow integrated pollution index (NIPI), were introduced to assess heavy metals (HMs) pollution. Results show that 72.05% of the sites are identified as moderate pollution, where Cd, As, and Cr(VI) are at heavy pollution, incorporating soil self-purification. The average values of potential ecological risk (PERI) reached 6615.00, posing a significant damage to the local ecosystem, and Cd was identified as main ecological hazards in the study sites. Furthermore, the health risk assessment shows that children's health risks are higher than that of adults, with non-carcinogenic risk to children (2.60) and adults (0.41), and carcinogenic risk to children (2.30 x 10-3) and adults (1.12 x 10-4). Utilizing a multi-index decision-making approach, it is determined that 19.30% of the site exhibit high-risk values, between concentration screening (11.40%) and risk screening (83.30%) base on single-indices. The study sheds light on the comprehensive assessment of brownfield site safety.